This invention relates to a process for separating aqueous insoluble, organic solvent-soluble solid components from solid compositions. More particularly, this invention relates to such a process wherein organic solvent-soluble solid components can be isolated from a solid composition by clarification and extraction conducted in the same apparatus.
At the present time a wide variety of solid compositions are treated to recover a solid component of the composition which is either a useful product or which renders the remaining solid composition a useful or safely disposable product. Such solid compositions include the solid portion of fermentation broths wherein the desired product comprises the solid component to be recovered, the solid portion of animal or plant tissue which comprises the solid compound to be recovered or solid toxins in solid wastes which are desired to be removed so as to render the remainder of the solid waste useful or in a form which permits its safe disposal.
At the present time, the solid biomass portion of a fermentation broth containing the desired water insoluble solid component is filtered and then redispersed by a multiple batch process in an organic solvent which selectively solubilizes the desired solid component. By utilizing a plurality of redispersion and filtration steps, the desired solid component can be effectively removed from the remaining solid biomass. The resultant dissolved solid component is recovered by conventional means such as by extraction, evaporation or with a water miscible solvent which is subsequently mixed with water to precipitate the desired solid component. Alternatively, the whole fermentation broth is admixed with a water-immiscible organic solvent. The resulting mixture is allowed to separate into two phases and the organic phase is decanted. Subsequently the desired product is recovered by precipitation and/or extraction. Alternatively, the whole fermentation broth is admixed with an organic solvent which is immiscible with water in order to selectively dissolve the desired solid component followed by filtration and reextraction with the water-immiscible organic solvent.
These processes are undesirable since they require multiple independent steps which require transportation of the treated material from step to step. This procedure is expensive and time consuming. In addition, the recovery rate of product is in the order of about 60% which is undesirably low. Furthermore, these processes increase personnel exposure to process fluids and of product to air borne contaminants.
Accordingly, it would be desirable to provide a process for recovering products from solid compositions which products are insoluble in water but soluble in organic solvents which can be effected in one step. In addition, it would be desirable to provide such a process which provides a high yield of uncontaminated product in the order of 90% recovery or higher.